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PRM150 leaks


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A friend has a hard to pinpoint oil leak from his PRM150. I too have a PRM150, but mine is rather lovely and wouldn't dream of doing such a thing to me, it's doting owner.  His is quite young, though it's long out of warranty due to sitting on the builders shelf so PRM are understandably not rushing to be responsible. It seems seems likely to be a seal as he says he has no signs of damage, but what are the common sources of said leaks and, prempting the results of the better informed search, which of the issues can be resolved with the gearbox in situ?

 

Thanks in anticipation. :)

 

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Can't comment on the leak but earlier today I had reason to look on the PRM site and seemingly the 24 month warranty period starts ticking from the day the box leaves their factory. This runs counter to most warranties which start from date of delivery to end user.

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One common one is the control lever seal, and if the box is fairly new it could be that the control/cable is maladjusted so when in gear it's under constant sideways pressure. Tell him to take the cable off the box, put it in gear (running) by hand and see if it leaks or of the leak has gone.

  • Greenie 3
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Also remind him that PRM, or any other manufacturer, has no duty to provide a warrantee. If they do, it is in addition to the purchasers' statuary entitlement. Depending upon the fault and the time he has had it, there may be a claim against the builder.

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I've known one or two that have leaked out of the drive shaft spraying a line of oil across the deck boards and around the engine compartment. Mine did this once for about a week, but stopped as soon as it started. The others I've seen require the drive shaft coupling removing and a new seal fitted.

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1 hour ago, Sea Dog said:

A friend has a hard to pinpoint oil leak from his PRM150. I too have a PRM150, but mine is rather lovely and wouldn't dream of doing such a thing to me, it's doting owner.  His is quite young, though it's long out of warranty due to sitting on the builders shelf so PRM are understandably not rushing to be responsible. It seems seems likely to be a seal as he says he has no signs of damage, but what are the common sources of said leaks and, prempting the results of the better informed search, which of the issues can be resolved with the gearbox in situ?

 

Thanks in anticipation. :)

 

 

 

Mine leaked slowly out the sump. The guy who originally reconditioned it said this was common for it to leak there regardless of what the internal issue was (the sump is the natural place for oil to escape when forced out by hydraulic pressure no matter how tightly it's screwed in). 

 

Initially he replaced some O-rings, and possibly the gasket (I believe PRM sell these as a kit and regard them almost as consumables) which he said was a common issue. This didn't work, I believe he also checked the control lever per Tony's suggestion. Eventually he replaced the oil pump, which he apparently discovered a microscopic crack in on returning to the workshop.

 

 

This appeared to resolve the problem, until what appears to have been a hydraulic failure without losing oil from the box itself, now outside his warranty. I hope my next PRM150 is a little more lovely

 

 

 

Edited by enigmatic
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Ours has a slight leak. I was told that overfilling the oil causes the seals to blow. I now measure the correct amount but too late me thinks. Never worked out whether the marks on the dip stick are correct when the stick is just dipped or when it is screwed down.

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1 minute ago, Midnight said:

Ours has a slight leak. I was told that overfilling the oil causes the seals to blow. I now measure the correct amount but too late me thinks. Never worked out whether the marks on the dip stick are correct when the stick is just dipped or when it is screwed down.

Dip stick marks. The top mark is with the stick screwed in, so fill to the bottom mark with the stick just dropped in but not screwed and you will be right.  Also make sure that the breather is clear, there should be no pressure whatever in the box when running.

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1 hour ago, Tony Brooks said:

One common one is the control lever seal, and if the box is fairly new it could be that the control/cable is maladjusted so when in gear it's under constant sideways pressure. Tell him to take the cable off the box, put it in gear (running) by hand and see if it leaks or of the leak has gone.

And of course if it leaks you must (as most on here already know) NEVER use any metallic tool to remove the old seal; you'll damage the bore and it will leak forever. Remove the nut to remove the lever; be ready to catch the spring and ball. Hold a cloth over the hole and crank the engine over to allow the oil pressure to expel the seal.

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1 hour ago, Midnight said:

Ours has a slight leak. I was told that overfilling the oil causes the seals to blow. I now measure the correct amount but too late me thinks. Never worked out whether the marks on the dip stick are correct when the stick is just dipped or when it is screwed down.

I think I am guilty of overfilling ours, and it now has a slight leak, but it only seems to loose the excess oil.  Not sure where it actually is coming from. Anyway having checked it today, it is (as best you can tell) just below the top mark, so should be fine until the the next oil change.  The engine and gearbox have done over 5000 hours now, so I can excuse a bit of a leak, and the engine still does not leak or burn any oil at all.

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Not helpful to the OP but my friend - who has the same engine and gearbox - when i mentioned i had a leak said:

 

Show me a PRM gearbox without a leak and i shall show you one without oil.

 

My leak was from the gearbox selector, new seal and it still leaked but less so! It also seems to find it's own level, so i fill it to the mark and then it drips a bit until it oozes, then stops. A drip try in place and no worries until the yearly oil change.

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On 24/08/2021 at 19:29, Ex Brummie said:

I've known one or two that have leaked out of the drive shaft spraying a line of oil across the deck boards and around the engine compartment. Mine did this once for about a week, but stopped as soon as it started. The others I've seen require the drive shaft coupling removing and a new seal fitted.

From outside or a gearbox out job?

On 24/08/2021 at 19:05, Slim said:

seemingly the 24 month warranty period starts ticking from the day the box leaves their factory.

His experience exactly.

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On 24/08/2021 at 19:22, Tony Brooks said:

Also remind him that PRM, or any other manufacturer, has no duty to provide a warrantee. If they do, it is in addition to the purchasers' statuary entitlement. Depending upon the fault and the time he has had it, there may be a claim against the builder.

Thank you for your advice in your first post Tony. The above is where he finds himself and why he's now looking to sort it himself.

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A number of interesting posts above folks, thank you all. Ni

 

Mine is as dry as you like, but it seems a that these boxes are designed along the lines of old Triumph motorcycle engines and a bit of oil is almost to be expected!

 

I'll be passing on all of the above, and filing a few gems away for future reference too!

  • Greenie 2
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My friend replaced the back seal with the gearbox in place, just disconnected from the prop shaft. 

When my PRM was new 32 years ago, on the first cruise over a fortnight, the gearbox got through a gallon of oil with a leak from the top gasket. The man came up from Duffield's who supplied the engine and removed the top to reveal coarse machining marks on the mating face of the lid. They trusted me to fir the replacement they supplied. 

The good thing about the PRM is that if it does leak oil then it stops working before destroying the bearings.

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We had an interesting gear box leak this week, owners said that they had topped it up and it had emptied in hours. They left the boat on Saturday. We couldnt feel or see any oil leak on Monday so emptied engine sump,  put down clean pads, filled it and ...still couldnt see any leak. Ran it up, and eventually saw some ATF oil on a nut on the Isuzu engine top.

One of the engine mounts was very loose, meaning more than usual vibration, heat exchanger not mounted, just sat on a bracket, who's nut had worn through the outer jacket.

 

20210826_070634.jpg

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